The effectiveness of polypeptides from phosvitin and eggshell membrane in enhancing the bioavailability of eggshell powder calcium and its accumulation in bones

Abstract

The low-calcium-specific pathogen-free C57BL/6 (SPF–C57BL/6) mice were used to explore the effectiveness of phosvitin phosphopeptides (PPPs) and eggshell membrane peptides (EMPs) in improving the intestinal calcium absorption and promoting bone deposition of eggshell calcium (ESCa). Intake of ESCa + PPPs + EMPs significantly down regulated the abnormal elevation of serum alkaline phosphatase (ALP) induced by calcium deficiency. The CaCO3 group had lower calcium absorption rate (34.34%) and femur bone mineral density (BMD) (0.13 g/cm3), while the ESCa + PPPs + EMPs treatment significantly improved calcium absorption rate (55.01%) and femur BMD (0.15 g/cm3). The three-dimensional reconstruction images of mice femur showed that the ESCa + PPPs + EMPs group had a more complete, compact, and thicker trabecular structure than the low-calcium, CaCO3, and ESCa groups. These results indicated that the ESCa is a low-cost alternative calcium supplement to achieve adequate calcium intake, and the presence of polypeptides, such as PPPs and EMPs, is more beneficial to calcium absorption and deposition than the ESCa.